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Directed self assembly (DSA) of block copolymers is an emerging technology for achieving sub-lithographic resolution. We investigate the directed self assembly of tw o systems, polystyrene-block-poly-DL-lactic acid (PS- b-PDLA) and PS-b-poly(methyl methacrylate). For the PS-b-PDLA system we use an open source EUVL resist and a commercially-available underlayer to prepare templates for DSA. We investigate the morphology of the phase separated domains and compare the LER of the resist and the PS-PDLA interface. For the PS- b-PMMA system we again use an open source resist, but the annealing conditions in this case require crosslinking of the resist prior to deposition of the block copolymer. For this system we also i nvestigate the morphology of the phase se parated domains and compare the LER of the resist and the PS-PMMA interface. Keywords: EUVL, LER, directed self assembly, block copolymers, PS- b-PDLA 1. INTRODUCTION With the continuous increase in demand for more powerful and energy efficient computing, higher capacity storage devices, and portable electronics, the rigorous transistor scaling driven by advances in lithography has entered its fifth decade. Among the various candidates for next generation lithography, extreme ultraviolet lithography (EUVL) is arguably the leading candidate to replace 193 nm immersion double pattering for the high volume manufacture of semiconductor devices. This platform is attractive due to the use of a short wavelength ( = 13.4 nm) photon source, which allows for single patterning steps and mask layouts. However, due to the delay in development of EUVL, 193 nm immersion double patterning has remained as the only viable technology for high volume manufacture for the 32 nm and possibly the 22 nm node. There are a number of factors which have contributed to this delay, with the most notable being the low source power. There are however, also issues with the photoresist that need to be addressed to meet the ITRS specifications for the 22 nm node. It is generally accepted that the most critical of these is line edge roughness (LER), which arises predominantly from shot noise and diffusion of photoacid in chemically amplified resists. There has been much work on the development of resists to overcome problems with LER. These include polymer bound PAG resists |
